Tobacco products are still widely available to adolescents through commercial sources. Curtailing retail sales to children is a crucial element of primary prevention of tobacco use by adolescents. In-store advertising and promotions are an escalating element of the merchandising strategy of the tobacco industry, and children are uniquely susceptible to these industry tactics. In addition to providing access to tobacco products, the retail environment may be an important stimulus for increasing demand among adolescents. It is not known what role a particularly pro-tobacco retail environment has on the likelihood that clerks will sell to minors, nor is it known to what extent sales to youth are reduced by other elements of the corporate culture or by community influences such as anti-tobacco activism. The aims of this study are to (1) estimate the national prevalence of retailer incentives, density of in-store tobacco advertising, and retail sales of tobacco to youth, (2) examine the relationship between tobacco merchant incentive payments and the degree to which the retail environment is pro-tobacco, and (3) test a comprehensive model of the predictors of sales of tobacco to minors, focusing on corporate, community, merchant, and store characteristics. We will use merchant interviews, in- store observations, and buy attempts by minors in a probability sample of 1,500 stores in 75 communities in 15 states. We will also develop strength of tobacco control scores for each community, using key informant interviews and archival data. We will investigate the influences of merchant associations, and of corporate parents of chain stores. We will determine the degree to which the retail environment and the rate of sales of tobacco to youth change over time. We will apply our experience, materials, and methods to create and disseminate a Tool Kit with which tobacco control activists can evaluate the retail environments in their own communities and enhance merchant compliance with tobacco age restrictions. This study will help guide decision-makers in selecting the most effective public policies. We will also be able to determine if increased strength of tobacco control at the community level modifies the nature of the retail environment and the rate of sales to youth, helping to inform best practices. This study will also provide first-time national estimates of the rate of illegal tobacco sales to minors, useful in understanding the impact of various efforts to reduce youth access from commercial sources. Finally, it will provide tools for communities and policy-makers to use to perform continuous monitoring of the retail environment.